Compensating switch for sonar



Sept. 1, 1970 GUUCK, JR" ET Al- 3,526,872

COMPENSATING SWITCH FOR SONAR 5 Sheets-Sheet 1 Filed NOV. 25, 1966 JOSEPH E GULICK, Jr. HARLAN H. KNAPP, Jr.

wzozmomci o A ORNEY Sept. 1, 1970 GULJCK, JR ETAL 3,526,812

COMPENSATING SWITCH FOR SONAR 5 Sheets-Sheet 5 Filed Nov. 25. 1966 O O O O B O O m o o E. O m m o H O O P l iill. m a m D O 0 M 0 o 0W6 o 9 o 4 O O O O O JOSEPH F GULlCK,Jr HARLAN H. KNAPP, Jr.

p 1970 J. F. GULICK, JR., ETAI. 3,526,872

COMPENSATING SWITCH FOR SONAR Filed Nov. 25, 1966 5 Shcets-5heet 4.

FIG. 6 HYDROPHONES PREAMPLIFIERS SW'TCH'NG sERvo' MOTOR SYSTEM LEFT RIGHT /45 DELAY LINE DELAY LINE OUTPUT OUTPUT COUPLING COUPLING CIRCUIT CIRCUIT l I l I I I l l I SUM AND I 90 a SHIFTER DIFFERENCE I I8 I I SWITCH I IV I I i BANDPASS FILTER I o I I l II I I I :& CLIPPER I I I I I I I 4 BANDPASS I l I FILTERS I PHASE DETECTOR I I I I l I I I FILTER I l I I I a l I I I E I I SPEAKER I I I7 E CHOPPER I I METER I I1 I I PHONES I g E I I I a: AMPL FIER I I J I L J I.

INVENTORS JOSEPH F. GULICK, Jr. HARLAN H. KNAPP,Jr.

Sept. 1, 1970 J.-F. GULICK, JR, ETAl. 3,526,872

COMPENSATING SWITCH FOR SONAR Filed Nov. 25, 1966 5 Sheets-Sheet 5 a0 F'IG..'?

INVENTORS JOSEPH E'GULlC-K,Jr. HARLAN H. KNAPP,Jr.

United States Patent 3,526,872 COMPENSATING SWITCH FOR SONAR Joseph F. Guliek, Jr., Clarksville, and Harlan H. Knapp, Jr., Silver Spring, Md., assignors to the United States of America as represented by the Secretary of the Navy Filed Nov. 25, 1966, Ser. No. 597,136 Int. Cl. G01s 3/00 U.S. Cl. 340-6 8 Claims ABSTRACT OF THE DISCLOSURE The present invention is an improved photoelectric switching system especially useful for sonar but which may have other applications. As used in a sonar system, the invention functions to route right and left channel hydrophone signals into linearly tapped delay lines and thence to information utilization apparatus and to a servosystem, so that the direction from which such signals emanate may be kept under constant surveillance. The invention is a substitute for the less efiicient mechanical switch used up to the present time.

The present invention relates to an improved photoelectric switching system. Although especially designed for connecting a predetermined combination of sonar hydrophones to selected taps on a plurality of delay lines, the invention may find use in any application requiring the selective switching of multiple inputs to a plurality of utilization devices.

Sonar switching systems in use up to the present time have been of the mechanical type, employing matrices which route left and right hydrophone signals into linearly tapped delay lines via slip rings and sliding contacts. A combination of a large number of stator contacts for both left and right signals are wiped by a plurality of brushes arranged on a rotating disk. Such a complex mechanical switch matrix presents a reliability problem. Another disadvantage of a mechanical switch of this type is the friction load presented to the servosystem. More specifically, the load produced by a large number of sliding contacts and slip ring brushes renders it diffioult to eliminate dead space in the servosystem. In addition, the need for frequent preventive maintenance has presented another serious problem. Thus, with a mechanical switching system a serious degradation of performance will result unless a continuous maintenance program is carried on.

The deterioration of system performance due to poor switch system reliability can be determined by considering the pointing error which results from the loss of a signal from a single hydrophone. Such an invesigation was performed with a computer simulation and the results indicated a peak error of .45 degree from a single missing hydrophone at a velocity of sound equal to 95 percent of the design velocity.

One object of the present invention, therefore, is to provide an improved photoelectric switching system that will perform electronically the functions that are presently effected mechanically, with a resultant improvement in reliability and a reduction in preventive maintenance requirements.

As a further object, the invention provides a switching system that will not present a significant friction load to the servosystem employed, with the result that dead space in said servosystem will be substantially eliminated.

Other objects and many of the attendant advantages of the present invention will be appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

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FIG. 1 is an exploded perspective showing the ap paratus employed in the system of the present invention, said apparatus including a pair of switch units mounted back-to-back for controlling right and left signal processing channels;

FIG. 2 is an enlarged detail section showing, as to one of the switch units of the system, the mounting of two of the photoelectric switches employed and the connection between a radial conductor on one of the switch disks and a concentric conductor on another disk of the same switch unit;

FIG. 3 is a front elevation, partially diagrammatic, showing a switch disk and mask in their proper relative positions, the mask being partially broken away to show a portion of the disk and the disk being partially broken away to show some of the radial conductors employed; 1

FIG. 4 is a diagram depicting the arrangement of the hydrophones, and the connections between one set of hydrophones and an associated radial conductor;

FIG. 5 is a detail schematic showing a typical connection between a pair of hydrophones and corresponding control switches on the switch disks of the switch units;

FIG. 6 is a block diagram showing how the switch of the present invention is connected in a sonar system;

FIG. 7 is a diagram illustrating the connections between three of the twelve sets of hydrophone control switches and their radial conductors and the switches for connecting the radial conductors with some of the delay line conductors;

FIG. 8 is a front elevation showing the conductor disk of one of the switch units, the view particularly illustrating the concentric conductors employed and being partially broken away to show a portion of the adjacent switch disk.

The switching system of the present invention functions to connect, as to each signal processing channel, of, say, a sonar system, a combination of transducers, or hydrophones, to a combination of taps on a delay line. The system includes a switch comprising a pair of switch units operating back-to-back, a delay line connected to each unit, and a servosystem. A switch unit is provided for each channel, and any hydrophone may be assigned to any tap on the delay line for that channel. Since the switch units are identical, a description of one will sufiice for both of them.

A typical switch unit includes a mask which is rotatable between a light source and a fixed switch disk, the mask being provided with transparent curvilinear portions or slots. The switch disk has thereon four quadrants, each quadrant consisting of, in a typical embodiment, sixteen spaced arcuate conductors on one face of the disk and twelve spaced radial conductors on the opposite face of said disk. For convenience in this description the radial conductors will be called radials and the arcuate conductors arcs. Photoelectric switches are mounted on the rim of the disk and are exposed by an arcuate cut-out portion on the disk. These switches are connected through appropriate amplifiers to hydrophones. Additional switches are arranged in rows on the disk and connect the arcs to the radials at points where said arcs cross said radials in close spaced relation thereto. The arcs are connected to taps on a delay line. From the foregoing it will be understood that in a given mask position, selected switches will be exposed through the curvilinear slots, for connecting the radials to selected arcs and thus to selected delay line taps. Since, as stated, the radials are connected to the photocells on the perimeter of the disk, selected hydrophones will be connected to the selected delay line taps. A second fixed disk is mounted behind the disk above described. On this second disk are positioned a plurality of concentric conductors which are connected to the radials on the first disk in such a manner that each radial in a quadrant will be connected to its corresponding radial in each of the other three quadrants.

The second switch unit, which operates back-to-back with the unit above briefly described, connects an adjacent group of hydrophones to selected taps on a second delay line.

The masks of the two switch units are mounted on a common shaft and are driven by a servomotor in response to an error signal. More specifically, if the target being tracked is directly ahead of the ship carrying the hydrophones, the hydrophones in the first quadrant of each switch will be activated. If the first switch in each quadrant has a maximum delay and the last one has a 7 minimum delay, a phase null condition will result. That is, the two signals at the outputs of the delay lines will be in phase. If, however, the target is located, say to the port side of the ship, the signals reaching one of the delay lines will differ from those reaching the other and an error signal will be produced, thus causing the servomotor to shift the masks until a null condition is again attained. Observation of the delayed signals can be made by suitable monitoring equipment connected to the output of the delay lines.

Referring now more particularly to the drawings, the arrangement of the switch is illustrated in FIG. 1. This view is necessarily diagrammatic and in exploded perspective, to show the mask, switch disk, conductor disk, light source, and lens of each switch unit, together with the means for rotating the masks. In practice, of course, many changes may be made in the interest of efiiciency and ease of manufacture without departing from the scope of the invention.

The two switch units of the switch, shown generally at 9, are mounted on opposite sides of a drive pulley 10, the switch unit to the left of the pulley 10 in FIG. 1 being designated switch unit A, and that to the right of said pulley being designated switch unit B.

The switch unit A includes a light source 11, a condensing lens 12, and a mask 14 which is pinned to a shaft 15 that is connected to the pulley 10. The mask 14 is formed of opaque material and is provided with four equidistant slots 16 and a peripheral cut-out 17 that extends throughout substantially one-fourth of the circumference of the mask. The slots 16 are of arcuate shape, specifically being developed from a polar plot of a cosine curve where the outermost extremity is zero degrees and the innermost point is ninety degrees. The switch unit A also comprises a switch disk 18 and a conductor disk 20, both of which are mounted in fixed positions by any suitable means (not shown). The switch disk 18 confronts the mask 14 and has on its front face, as seen in FIG. 1, a plurality of arcuate conductors, or arcs, 22 arranged in spaced quadrants a, b, c, and d and with the arcs of each quadrant arranged concentrically. On the rear face of the disk 18 are positioned a plurality of equally spaced radial conductors, or radials, one of which is shown at 24 in FIG. 2. On the rear face of the conductor disk is a plurality of concentric conductors, one of which is shown at 26 in FIG. 2. The radials 24 are connected to the concentric conductors 26 by leads 28, so that each radial is connected to its corresponding radial in each of the four quadrants.

Mounted on the outer rim of the disk 18 and facing the mask 14 is a plurality of equally spaced hydrophone switching photocells 30, hereinafter called control switches. Also mounted on the disk 18 and confronting the mask 14 are delay line switches 31. The switches 31 are arranged in rows and are mounted so that they will, when exposed to light, connect the arcs 22 to the radials behind them, one of the switches 31 being located at each point where an arc crosses in front of a radial.

Referring now to the switch unit B, shown to the right of the pulley 10 in FIG. 1, a conductor disk, a switch disk and a mask are shown at 32, 34, and 36, respectively. The mask 36 has a peripheral cut-out 37. A second condensing lens and a second light source are shown at 38 and 40, respectively. The disks 32 and 34 and mask 36 are identical in construction and arrangement to the disks 20 and 18 and the mask 14, and the lenses 38 and 12 and light sources 40 and 11 are similar. It should be noted that the pulley 10 also serves to shield the switch units A and B, so that the light sources 40 and 11 will not interfere with each other.

It should be understood that the shaft 15, which is connected to the mask 14 and the pulley 10, is also connected to the mask 36, and that the disks 32 and 34 are rigidly mounted. It will thus be seen that rotation of the pulley 10, as by a motor 42 and a belt 44, will rotate the masks 14 and 36 simultaneously. However, since the switch units A and B are mounted back to back, corresponding slots 16 in the masks 14 and 36 will confront adjacent quadrants on each side of a center line extending axially through the switch section.

In the embodiment shown there are forty-eight of the radials 24 on each of the disks 18 and 34, twelve on each quadrant. There are forty-eight transducers, or hydrophones, in the system, two of them being shown diagrammatically at 46 in FIG. 5. There is a control switch 30 mounted at the outer end of each radial. Each hydrophone 46 is connected to a pair of radials in opposite quadrants through a preamplifier 47 and a corresponding control switch 30 on each of the disks 18 and 34. For example, as shown in FIG. 5, a hydrophone connected to the first switch 30 on quadrant a on the disk 18 would also be connected to the last one, i.e., the forty-eighth, on quadrant d on disk 34.

Under the condition mentioned hereinabove by way of example, i.e., when a target being tracked is directly ahead of a ship utilizing the instant system, the peripheral cutout 17 on the mask 14 will expose the control switches 30 for the twelve radials in the quadrant a on the disk 18. Since these radials are connected to their corresponding radials in the quadrants b, c, and d by the concentric conductors 26 and leads 28, all of said radials on said disk 18 will be energized. However, only the hydrophones that are connected to the exposed peripheral switches 30 will be connected to the radials. Under the same condition the peripheral cut-out on the disk 34 will expose the control switches 30 of the quadrant a of said disk. The disks 18 and 34 are, as stated, mounted in reverse relationship, a different group of hydrophones will be connected to the radials of quadrant a of the disk 34. In more detail, the hydrophones connected to the twelve switches 30 in quadrant a of the disk 18 are also connected to the twelve switches 30 in quadrant d of the disk 34. When the cut-out 17 of the mask 14 is exposing the switches in quadrant a of said disk 18, the mask 36 will cover the switches of quadrant d of disk 34. Similarly, when the cut-out 37 in the mask 36 is exposing the switches 30 of the quadrant a of the disk 34, the mask (114kWill cover the switches 30 of the quadrant d of the From the foregoing description it will be seen that although twelve of the control switches 30 are exposed on, say, the disk 18 'by the cut-out 17 on the mask 14, and all of the radials 24 on the disk are thus energized, only those radicals that are connected to arcs 22 by delay line switches 31 exposed through the slots 16 will connect hydrophones to taps on a delay line 48. A delay line 48 is provided for each switch disk, and the arcs 22 of all four quadrants of each said disk are connected to a delay line, so that each delay line has sixty-four taps. In this connection, it should be noted that, as best seen in FIGS. 1 and 3, the quadrants a, b, c, and d on the disks 18 and 34 are arranged so that the arcs thereof are positioned concentrically, and by way of example, the arcs 22 of one quadrant of the disk 18 are offset slightly with respect to those of adjacent quadrants. This arrangement assures that the slots 16 of the mask 14 will expose differ- ;ent switches 31 on each quadrant in a given mask position. In a practical embodiment, no more than twelve of the switches 31 would be exposed for each mask position, with the result that no more than twelve delay line taps would be connected to a selected group of hydrophones.

Reference is now made to FIGS. 4 and 7 of the drawings, wherein it will be seen that as to each switch disk (18 or 34), hydrophones are connected to the disk in 12 sets of four, with a hydrophone in each set connected to a control switch 30 in each quadrant. In FIG. 7, which shows a simplified switch matrix, the control switches 30 and one of the concentric conductors 26 to which they are connected are illustrated in schematic, the radials 24 being shown collectively. From a study of these views it will be clear that corresponding control switches in each quadrant of each disk (18 or 34) are connected together, e.g., switches 1, 13, 25 and 37, and 2, 14, 26 and 38, and so on.

In FIG. 6 the connections of the switch in a sonar system are shown. The outputs of the delay lines 48 are connected through appropriate coupling circuits to a utilization circuit that terminates in suitable translating means, such as a loudspeaker, an offset meter, and/or a headset. The output circuits from the delay lines are also connected to a servosystem that includes a phase shifter, a bandpass filter, a clipper, a phase detector, chopper and amplifier. The output of the amplifier is connected to the servomotor 42.

In operation, let it be assumed that a target is located dead ahead of the ship carrying the sonar receiving set, and that the masks 14 and 37 of the switch units A and B, respectively, are positioned for exposing the switches 30 of the quadrants a of the switch disk 18 and 34. Such exposures will result in the connection of twelve hydrophones to the radials of the switch disk 18 and twelve hydrophones to the radials of the switch disk 34. Since, as previously explained, the switch units A and B are mounted back-to-back, the group of hydrophones connected to the radials of the disk 18 will be different from that connected to the radials of the disk 34. That is, and referring to FIG. 4, hydrophones '1 and 12 will be connected to the switch disk 18 and hydrophones 37 through 48 will be connected to the switch disk 34.

The slots 16 in the masks 14 and 36 will, with said masks in the positions noted above, expose certain of the switches 31 in each quadrant of each disk for connecting certain hydrophones with certain delay line taps. The slots 16 and the quadrants are so arranged that only selected delay line taps will be connected. For example, if hydrophone No. 1 of each quadrant a has the maximum delay and hydrophone No. 12 has minimum delay, a null condition will exist if these hydrophones are connected, respectively, to taps Nos. 1 and 64 of the delay lines. That is, the phase difference between the signals from the two delay lines will be zero. If, however, the target should be located toward, say, the port side of the ship, there will be a differential delay in the arrival time of the reflected signals at the hydrophones in each quadrant, with the result that the phase difference between the signals will be proportional to the pointing error. For example, if the reflected signal is emanating from a point 30 degrees to port, the phase of the composite signal at the output of the left delay line 'will lead that of the signal at the output of the right delay line, producing an error voltage. This error signal will cause the system to seek a new null condition by effecting the operation of the servomotor for shifting the masks 14 and 37.

What is claimed is:

1. In a photoelectric switching system having a plurality of transducer means, signal delaying means, a servosystem, and information utilization means:

a first switch unit having photoelectric switch means,

a second switch unit having photoelectric switch means,

' means connecting said switch units to said transducer means,

means connecting said switch units to said signal delaying means, and

means connecting said signal delaying means to said servosystem and to said information utilization means,

said servosystem being operable in response to a signal from said transducer means for actuating said switch units whereby information as to the direction of a signal impinging on said transducer means will be supplied to said information utilization means.

2. The invention recited in claim 1, wherein each of the switch units comprises:

a light source,

a lens for the light source,

a switch disk having photoelectric switch devices thereon, and

a mask rotatable between the switch disk and the lens, said mask having openings for exposing certain of said photoelectric switch devices to light passing from said light source through said lens.

3. The invention recited in claim 1, wherein each of the switch units comprises:

a light source,

a lens,

a switch disk having radial conductors on one face thereof and arcuate conductors on the other face thereof,

photoelectric control switches on the switch disk and connected with the radial conductors,

photoelectric delay line switches on the switch disk and connected between the radial conductors and the arcuate conductors, and

a mask rotatable between the switch disk and the lens, said mask having openings for exposing certain of said control and delay line switches to light passing from said light source through said lens.

4. The invention recited in claim 3, wherein the servosystem includes a motor,

a shaft mounting the mask,

a pulley on the shaft, and

means operatively connecting the motor to the pulley.

5. The invention recited in claim 3, wherein the switch units are mounted back-to-back, and

including a common shaft rotatably mounting the masks of the switch units.

6. In a photoelectric switching system having a plurality of transducers, a pair of tapped delay lines, a servosystem, and information utilization means:

a pair of switch units each having a switch disk, a light source and a mask between the light source and the switch disk, the masks of said switch units being mounted on a common shaft,

radial conductors on each of the switch disks,

arcuate conductors on each of the switch disks,

photoelectric switch means on each of the disks for connecting the radial conductors thereof with the transducers,

photoelectric switch means on each disk for connecting the radial conductors with the arcuate conductors,

means for connecting the arcuate conductors of one of the disks to taps on one of the relay lines,

means for connecting the arcuate conductors of the other of the disks to taps on the other delay line,

each of said masks confronting a switch disk and having a cut-out for exposing to light from the light sourec certain of said first mentioned photoelectric switch means for connecting a group of transducers to selected radial conductors, and having slots for exposing to light from said light sources certain of said second mentioned photoelectric switching means for connecting said selected radial conductors to selected arcuate conductors, whereby selected transducers of said group of transducers will be connected to a delay line, and means connecting the delay lines to the servosystem,

8 whereby the corresponding radial conductors of each quadrant of each switch disk will be connected together. 8. The invention as recited in claim 6, wherein, as to each switch disk, the arcuate conductors are mounted on one face of said disk and the radial conductors are mounted on the opposite face thereof.

References Cited UNITED STATES PATENTS 10 3,108,251 10/1963 Corbett 340-l6 3,160,350 12/1964 Dudley 3406 RICHARD A. FARLEY, Primary Examiner US. Cl. X.R. 

